Growth--differentiation Balance: a Basis for Understanding Southern Pine Beetle--tree Interactions

l.~rio, P.L., Jr., 1986. Growth--different iat ion balance: a basis for understanding southern pine beetle--~ree interactions. For. Ecol. Manage., 14:259-273 . Interrelationships between the southern pine beetle (SPB), Dendroctonus frontalis Zimm.) and its host pines are explained in terms of the growth--differentiat ion balance concept. A general hypothesis is proposed based on growth--differentiat ion balance in southern pines (radial growth of stems versus synthesis and yield o f oleoreain) and seasonal activity of the SPB based on knowledge from experimentat ion and observations reported in the literature. The spring appears to be particularly favorable for successful SPB attack because of the strong demand for available photosynthates by growth proceases at that time, whereas, in the summer, strong resin flow increases the potential resistance of trees to attack. Growth--differentiat ion balance provides a basis for understanding SPB-tree interactions, a rationale for commonly experienced problems in identifying consistent precursors to SPB outbreaks, and a philosophical basis for future research. The concept has potential application to other bark beetle--host conifer relationships.